1. Technical Field
The present invention relates to an image display device, a brightness control method, and a brightness control program.
2. Related Art
As a digital still cameras (DSC), there is known one mounted with an optical finder (see JP-A-2007-33701). Also, instead of the optical finder, there is known a DSC mounted with an electronic view finder (hereinafter, referred to as an “EVF”). The EVF displays image data generated by an imaging element of the DSC on a liquid crystal screen installed in an inner space of a finder window of the finder.
In the DSC mounted with the EVF, finder image disorientation as disclosed in JP-A-2007-33701 is particularly problematic. In other words, when a user continues to view images displayed on the liquid crystal screen through the EVF, the user feels dizzy, seems to feel disorientated, or feels an unpleasant pressure behind the eye. This dizziness, disorientation or discomfort (hereinafter, collectively referred to as “disorientation”) is thought to be because the user feels uncomfortable due to the EVF displaying images with a constant brightness (brightness brighter than the ambient light) regardless of the brightness of the ambient light, or because a luminosity difference between the space containing the liquid crystal screen as the EVF and the liquid crystal screen is great, or the like.
In the case of the optical finder, since the brightness of images which a user views through the finder window of the finder is not brighter than ambient light, the above-described “disorientation” is not greatly problematic. In addition, the EVF mounted in the DSC until now is relatively low in terms of the luminance of the liquid crystal screen or the resolution, and thus a user hardly feels “disorientated” as described above. However, hereafter, as a user uses the EVF more and more and luminance and definition of the EVF are increased, it is thought that the generation of the “disorientation” of a user is further problematic.